fix recurseve mutex on Android

android/src/main/cpp/main.cpp

@@ -16,6 +16,7 @@
  */
 
 //BEGIN_INCLUDE(all)
+#include <mutex>
 #include <initializer_list>
 #include <memory>
 #include <jni.h>
@@ -51,6 +52,7 @@ typedef void (*fnDebugMessageCallback)(GLDEBUGPROC callback, const void* userPar
 
 EGLDisplay g_display = EGL_NO_DISPLAY;
 EGLContext g_context = EGL_NO_CONTEXT;
+std::recursive_mutex mutex;
 
 jint JNI_OnLoad(JavaVM* vm, void* /*reserved*/)
 {
@@ -124,7 +126,7 @@ int GetUnicodeChar(struct android_app* app, int eventType, int keyCode, int meta
 
 void android_async_lock(struct engine* engine)
 {
-    pthread_mutex_lock(&engine->app->mutex);
+    mutex.lock();
     eglMakeCurrent(engine->display, engine->surface, engine->surface, engine->context);
 }
 
@@ -136,7 +138,7 @@ void android_async_swap(struct engine* engine)
 void android_async_unlock(struct engine* engine)
 {
     eglMakeCurrent(engine->display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
-    pthread_mutex_unlock(&engine->app->mutex);
+    mutex.unlock();
 }
 
 struct locker